I cannot get the PDF file when trying to import from this page:
https://www.sciencedirect.com/science/article/pii/S030193220500145X

Instead of the CAPTCHA page, I get:
https://s3.amazonaws.com/zotero.org/images/forums/u265723/kwvolchslu9mkmc8euqo.png

Debug ID: D1471819678
Zotero 7.0.0-beta.73+398454f85 (64-bit)
Windows 10

Same as reported here: https://forums.zotero.org/discussion/comment/460514/#Comment_460514

I have tried again just after making this bug report, and the PDF file was successfully imported, without any CAPTCHA:
Debug ID D1959104748

Exactly the same sequence happened yesterday when trying to report the problem.